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<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    // 改变this指向
    //function fn () {
    //  console.log(this)
    //}
    //fn.call(s)
    //function s () {
    //  console
    //}
//    function fn () {

//    }
//    fn.prototype.mony = function () {
//      console.log(123)
//    }
//var s =     new fn
//console.log(s)
var arr = [1,4,24,243]
 var s = arr.some( (item, index) => {
    return item == 4
  })
  console.log(s)
  </script>
</body>
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